Combine ingredients in a cocktail shaker with ice and shake vigorously until the mixture is nice and foamy. Strain into a chilled highball glass over ice.
*Cook's Note: Sugar syrup is a solution of equal parts sugar and water that is cooked over low heat until clear, then boiled for about 1 minute. Cool and store in a squeeze bottle and use to sweeten drinks, to taste.
Recipe courtesy The Cookworks